I would like to display all of this to the user somehow, like using a stack panel of elements where the first is a TextBox to display OrderName and the second is a Datagrid to display the list of Parts?

Honestly I am trying many different things (I have no requirements on what type of controls to use) but I can never get the PartsList to show correctly (either I get nothing OR I get "Collection" show to the user.

The goal would be to see something like this:
....Order1....Part1 7
..................Part2 12
....Order2....Part1 100
..................Part2 1
..................Part3 58
(dots are only there because spacing was off, should be spaces)